<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>定位可以越过padding</title>
    <style>
      .outer {
          width: 400px;
          height: 400px;
          background-color: skyblue;
          padding: 20px;
          position: relative;
      }
      .inner {
          width: 100px;
          height: 100px;
          background-color: purple;
          /*开启绝对定位*/
          position: absolute;
          /* 越过了padding*/
          top: 0;
          left: 0;
      }
    </style>
</head>
<body>
    <div class="outer">
        <div class="inner"></div>
    </div>
</body>
</html>